Reenforced elliptical oil cooler



July 29,1947. UR S 2,424,795

. REENFORCED ELLIPT-ICAL OIL COOLER Filed Jan. 15, .1945 '2 Shets-Sheet1 fiuly 29', 1947. B. BURNS REENFORCED ELLIPTICAL OIL COOLER Filed Jan.15, 1945 2 Sheets-Sheet 2 Imvcmor: BRUCE BUR/Y5 Patented July 29, 1947REENFORCED ELLIPTICAL OIL COOLER Bruce Burns, Los Angelcs, Calif.,assignor to The Garrett Corporation, Airesearch Manufacturing Companydivision, Los Angeles, Callt, a corporation of California ApplicationJanuary 15, 1943, Serial No. 472,462

2 Claims. (Cl. 257-128) My present invention relates to radiators, andrelates in particular to a radiator especially adapted for the coolingof oil from the crank case of an internal combustion engine, and whichis especially suited for aircraft installation.

It is an object of the invention to provide an oil cooler having greatercapacity for a given height than can be obtained by use of the commonlyemployed cylindric type of oil cooler construction. In air craftit isquite often found that the space to receive the oil cooler is limited invertical dimension and that an oil cooler of cylindrical form whichwould flt into this space will not have an oil cooling capacitysufficient to cool the aircraft engine with which it is to be used, thusmaking it necessary to employ a pair of small cylindrical oil coolers intandem relation.

It is an object of the present invention to provide a cooler offlattened, elliptical form which is amply strong to withstand thepressures developed in the oil cooling system to which it is connected,without excessive weight, and, due to its increased width as compared toits height, having much larger capacity than is obtainable from acylindric cooler of the same height.

It is an object of the invention to provide an oil cooler having a shellwhich is tubular, that is to say, has the general characteristics of atube in that it is open, from front to rear, this shell being flattenedto substantially elliptical form, the shell having tension platesextending substantially parallel to the minor axis and from front torear of the shell, these tension plates also acting as bafiles fordirecting the flow of oil to be cooled along a tortuous path through thecooler. It will be understood that the crossseotion of the shell neednot be a true ellipse, but portions of the shell which lie in transverserelation to the minor axis of the shell may be substantially parallel tothe major axis of the shell for a considerable distance. In thepreferred practice of the invention, however, the shell is continuouslycurved in the direction corresponding .to its circumference.

It is an object of the invention to provide an oil cooler of flattenedor elliptical form with rounded ends, and which is relatively strong forits weight, by reason of the employment in this cooler of the simple andeffective manner in which it is reinforced by a jacket member which alsoprovides ducts for the flow of oil to the inlet opening of the coolershell and which provides warm -up channels effective in the transmission of heat through the wall of the shell into 2 the interior of thecooler to thaw out the oil in the marginal portions of the cooler duringstarting periods.

It is an objectof the invention to provide a cooler of the classdescribed h'aving bafile so formed that zig-zag flow channels arprovided along the inner surface of the cooler shell from the inlet tothe outlet of the shell, in which passages cold or sluggish oil mayreceive heat which been conveyed through the wall'of the shell from hotoil in the warm-up passages formed by the jacket which reinforces thecooler shell.

It is a further object of the invention to provide a means foreffectively reinforcing theflattened shell of an oil cooler of thecharacter described herein, such means comprising tension plates havingflanges on their extremities, these flanges being secured to the shellso that forces acting within the shell and tending to deform the samefrom elliptical to cylindric form are carried by these tension plates.

I Further objects and advantages of the invention will be brought out inthe following part of the specification.

Referring to the drawings which are for illustrative purposes only,

Fig. l is a perspective view of a preferred embodiment of my invention,having portions cut' away so as to show internal construction.

Fig. 2 is a sectional view taken substantially as indicated by the line2-2 of Fig. 1.

Fig. 3 is a sectional view taken as indicated by the line Zi3 of Fig.2-.

Fig. 4 is a perspective view of one of sion plates employed in thecooler.

Fig. 5 is a fragmentary section showing a manner in which the plate maybe connected to the cooler shell by use of flange members.

Fig. 6 is a fragmentary sectional View similar to Fig. 5, but showingone of the flanges int tegrally formed on the edge of the tension plate.

Fig. 7 is a fragmentary perspective view showing the arrangement oftubes adjacent a tension plate.

Fig. 8 is an enlarged fragmentary section showing a wall of the coolershell and the manner in which the jacket is secured thereon.

Referring to Figs. 1 to 3 inclusive, the cooler the tenhas a shell itwhich consists of a metal sheet ii of elongated form, curved to form acontinuous loop, with the ends :2 thereof joined so that the sheet thenforms a short tube flattened, as shown in Figs. 1 and 3, so that incross-section it will have the general form of an ellipse, the majoraxis of which is nearly twice the length -3 of its minor axis. Forconvenient reference, the shell is described as having a front end F, arear end R, and sides S. At its leftside, toward the rear end, the shellhas an inlet port l3, and at ,its opposite, or right side, near itsfront end has an outlet port 14. The interior of the shell is dividedinto consecutive sections 15 by tension and baflle plates I8 lying inplanes which are transverse with relation to the major axis of the shelland extend from front to rear of the shell. These plates It, as shown inFig. 2, are preferably parallel to each other and to the longitudinalaxis of the shell, and, as shown in Fig. 3, are parallel to the minoraxis of the shell and accordingly at right angles to the major axis ofthe shell.

- The plates (3, as shown in Fig. 4, have therein openings l I toprovide intercommunication be tween adjacent chambers or sections 15which the plates [6 segregate within the shell Ill. The extreme upperand lower openings l1 comprise notches in the upper and lower edges ofthe plates so that when the plates are in operative position within theshell, the wall of the shell will form one boundary of each of theopenings l1. Therefore, the openings ll are brought into closestpossible proximity to the wall or sheet I I from which the shell i isformed. The openings I1 and ii are disposed alternately at the front andrear ends of the plates l6 within the shell [0, as shown in Fig. 2, sothatoil flowing through the interior of the cooler from the inlet l3 tothe outlet M will flow through the zigzag path indicated by the arrowsI8 of Fig. 2 from rear to front and front to rear of the cooler.

The upper and lower edges of the plates l are tied to the upper andlower portions of the shell so that these plates It not only serve asbaflle plates for directing the flow of oil in a desired manner throughthe interior of the cooler, but effectively restrain the upper and lowerwall portions of the shell in from moving or deflecting upwardlyanddownwardly respectively, when oil pressure is built up in thesections I5 of the cooler and tends to deform the shell from anelliptical tube to a cylinder. For attachment of the plates lBto theshell HI flanges l9 are secured to the upper and lower edges of theplates l6, as shown in Fi 5. by use ofwelds 20, and these flanges l8 arein turn firmly secured to the wall ll of the shell in by welds 2|. InFig. 6 I show a plate attaching means consisting of an angle 22 weldedat 23 adjacent an oppositely extending flange 24 which is bent on theedge of the plate IS. The angle 22 and the flange 24 are connected by.welds 25, to the wall or sheet I I of the shell I0.

Although not shown in Fig, 2, it will be understood that each of thesections i'5 contains a bundle of tubes 25 through which a heatabsorbing fluid, ordinarily air, may flow from front to rear of thecooler in the known manner of cooler construction.

As shown in Fig. 7, these tubes 25 have at their ends tubular walls 26and 21 of two separate cross-sectional configurations. These tubularwalls or enlargements 26 are joined together by solder and cooperate informing closures for the front and rear ends of the sections I5. Thetubular wall 26 are hexagonal and the tubular walls 21 are pentagonal soas to be placeable one upon the other along a side of a plate 16 in themanner shown in Figs. 1, 3, and 6. The

tubular walls 21 have side sections 28 for engagement with 'a plate I6,upper and low r S tions 29, perpendicular to the sections 28, for

engagement with similar sections on the ends of- Being flat, orsubstantially flat, the baflle plates l6 are non-distensible andconsequently are adapted to function as tie elements for securely tyingtogether the opposite sides of the shell across the minor axis thereofso as to prevent any appreciable distortion of the shell under theexpansive pressure of .the oil being forced therethrough. It is to benoted that even a slight amount of expansion of the shell across itsminor axis would result in pulling of the shell away from the adjacenttubes or pulling of the tubes apart so as to cause a leak in the cooler.

The shell III is surrounded by a jacket 32 which has'a dual function,namely, that of strengthening the shell and of providing channels for awarm-up flow of oil. As clearly shownfin Fig. 3, the jacket 32 comprisesupper and lower halves 33 and 34 although it is preferably formed from asingle elongated sheet of metal 35 so as to be in fact a substantiallysingle piece member which extends around the exterior face of the shelll0 and. has parts thereof joined to the shell. The edge portions 36 ofthe sheet 35 engage edge portions of the shell l0 and are connectedthereto by seam welds 31, although spot welding may be employed for thispurpose and the joint between the edge portions 36 and the edges of theshell l0 sealed by use of solder. mean a progressively formed continuousspot weld or resistance weld.

Between the edge portions 33 thereof, the sheet 35 is formed withchannels or depressions 38 and 39, the channel 36 occupying a centralposition with respect to the front and rear ends of the cooler and thechannels 39 being placed on opposite sides of the channel 38. Thesechannels 38 and 39, as shown in Fig. 8, each consists of a pair ofspaced side walls 40 extending inward from the outer wall 4! of thejacket 32, and the bottom wall 42 connecting the inner edges of the sidewalls 40, this bottom wall 42 engaging the surface of the shell l0 andbeing secured thereto by a seam weld 43.

As shown in Fig. 2, the channel 38 extends entirely around the rightside of the shell so as to divide the jacket 32 into front and rearhalves. As shown in Figs. 1 and 3, the channels 39 are discontinued atpoints 44 at the right hand side of the cooler so that they will notpassacross the jacket spaces 45 and 46. At the left side of the shellall three of the upper and lower channels 38 and 39 are discontinued atthe points 41 so as to leave at the left side of the jacket a continuouschannel or space 48 which communicates with the jacket passages 49 and50 which exist between the channel 38 and 39 and also with the inletport 13 of the shell. It will be noted that the passages 49 communicatewith the chamber 45, Fig. 2, and that the passages 50 of the jacketcommunicate with the chamber 46. In spaced relation to the right side ofthe cooler there is an attachment plate 5| to which a control valve 52may be secured, whereby inlet duct 53, outlet duct 54, and bypass duct55 may be connected to the interior of the control valve 52 and to thespaces of the cooler, as shown in s Fig. 2. i

The inlet duct 53 connects with the inlet chamber 45 of the jacket. Theoutlet duct 54 connects By seam weld wedelivered by the valve 63 withthe outlet port i4 of the shell and extends through a portion of thechamber 46. The bypass duct 55 connects with the chamber 46. Duringnormal operation of the cooler, oil to be cooled is conducted into thevalve 52 through oil inlet pipe 56 and is transmitted through the inlettraverses the path indicated by the arrows l8.

Should there be an increased resistance to flow of oil through thecooler resulting, for example, from congealing of oil in the spacesbetween the tubes 25, the bypass valve mechanism of the valve 52 willopen and permit oil to flow from the chamber 48 rightward through thejacket passages 50 as indicated by the arrows 60 of Fig. 3, to thechamber 46 from whence the oil will flow, as indicated by arrows 6|,through the bypass duct 55 to the control valve 52. In this event hotoil will flow from the-chamber 45, Fig. 2, leftward through the jacket,passages 49 to the leftward ends of the jacket passages 50, and thenright ward through the jacket passages 50 so as to be 52 into the oilreturn pipe This bypass flow of oil through the jacket passages 49 and50 will heat the shell "I, and the shell ID will conduct heat to the oilwithin the cooler contacting the inner face of the shell, therebyincreasing the fluidity of the oil in contact with the inner face of theshell, so that due to the pressure differential existing between theinlet port l3 and the outlet port ll of the shell,

transverse relation to the major axis of said shell, said plates havingin alternate order openings near the front and rear ends thereofconnecting said spaces so as to form a continuous zigzag passage withinthe interior of said shell, there being tension bearing connectionsadequate to withstand the full loads imposed on said shell byfluid'underpressure therewithin, tying the upper and lower portions ofsaid plates to said shell so that said plates will act in tension toprevent deformation of said shell toward cylindrical form under saidpressure; tubes for a heat absorbing medium extending through saidspaces from front to rear of said shell, there being means at the endsof said tubes cooperating therewith to close the front and rear ends ofsaid spaces; means supported on the cooler to form let port and a bypassport; and a jacket on the exterior of said shell, said jacket comprisinga metal wall corrugated so that edge portions and intermediate portionsthereof will engage the shell, said edge portions and said intermediateportions being seam-welded to the outer face of said shell so thatsaidjacket will reenforce said shell and form passage meansfor said inletport to said inlet opening, and from said first named passage to saidbypass port. 4

2. In a cooler of the class described, the combination of: an ellipticalshell having an inlet and outlet for passing oil into and out of theinterior of said shell; plates dividing the interior of said shell intoa plurality of spaces and connected v to thefltop and bottom of saidshell to reenforce a flow of such oil may be started along the top andbottom portions of the sections l5 and through the openings II' in theupper and lower edges of the plates l6 which connect the upper and lowerportions of the sections IS in series so as to define a zigzag path offlow for oil, such path of "flow lying in contact with the inner face ofthe shell and therefore in the zone heated by conduction of heat throughthe shell from the hot oil which flows through the jacket passages 49and 50. This relationship between the jacket passages, the shell, andthe openings ii in the plates l6 results in a condition in the coolerwhich 'contributes to rapid warming up of the same from a cold orcongealed state whereby maximum effectlveness of the cooler is obtained.

I claim as my invention:

1. In a cooler of the class described, the combination of: a tubularshell flattened so as to have approximate elliptical form with its majoraxis horizontally disposed and its minor axis vertically disposed, saidshell having an inlet opening at one side thereof and an outlet openingat the other side thereof; spaced substantially fiat plates extendingfrom the top to the bottom of said shell and from front to rear of saidshell, said plates dividing the interior of said shell into a pluralityof side by side spaces disposed in the same against deformation, saidplates having in alternate order openings near the front and rear endsthereof connecting said spaces thereby to provide a continuous zigzagpassage within the interior of said shell; tubes for a heat absorbingmedium extending through said spaces from front to rear of said shell;and a reenforcing member surrounding said shell and forming a series ofside by side warm up passages along the exterior of the shell, havingportions spaced from the shell to form theouter walls of said passagesand having other portions extended inwardly to the shell and weldedthereto to form the side walls of said passages and provide reenforcingsupport to the shell.

BRUCE BURNS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS an inlet port, an outconducting hot oil from

